Striking device of a power tool

ABSTRACT

A striking device of a power tool includes a striking room, two striking blocks and a transmission shaft. The striking room has a pivotal restricting groove at its two sides respectively, and two supporting surfaces formed adjacent to two sides of the pivotal restricting groove. Each striking block has a projected pivot formed axially, pivotally installed between two pin holes of the striking room via two pins. Two sides of the projected pivot are extended with striking portions, and the transmission shaft has two restricting blocks provided with a struck segment and a displacing segment. When one of the striking portion strikes one of the struck segments, the other of the striking portions just leans on the supporting surface to activate the transmission shaft to rotate. When the striking portion moves away after striking, it passes through the corresponding displacing segment to carry out next strike.

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention relates to a striking device of a power tool, particularly to one able to advance its strength for preventing it from damaged caused by deformation.

2. Description of the Prior Art

As shown in FIGS. 1 and 2, a first conventional power tool possesses a striking set 10 in its front portion. The striking set 10 is composed of a striking room 11 having an empty zone 101, two striking blocks 12 installed in the striking room 11, two positioning pins 13 inserted through the wall of the striking room 11, two sidewalls 121 of the striking blocks 12, and a transmission shaft 14 installed through the empty zone 14. The striking room 11 is driven to rotate by a power that is not shown in Figures. The transmission shaft 14 is provided with two restricting projections 141 spaced apart to be located at the upper and the lower end of the portion positioned in the striking room 11, respectively confined in the striking blocks 12. The front portion of the transmission shaft 14 positioned outside the striking room 11 is formed as a working head 142 for matching with diverse sockets to screw a bolt head or a nut. In using, when the striking room 11 is driven by a power to spin clockwise or counterclockwise, one of the positioning pins 13 linked with the striking room 11 is to hit at one of the striking blocks 12 to squeeze one of the restricting projections 141, to enable the transmission shaft 14 to rotate clockwise or counterclockwise for tightening or loosening the bolt head or the nut. However, as we know, the striking force is concentrated to the positioning pins 13 while operating the striking set 10. When the working head 142 confronts resistance more and more, it is to inversely keep the restricting projections 141, the striking blocks 12, and the positioning pins 13 receives torsion more and more, prone to pose the positioning pins 13 tortured to get damaged. Moreover, it is a single pivot between the wall 111 and the positioning pins 13. As all components of the striking set 10 have their own unchangeable sizes designed in a power tool, the part (A) of the wall 111 of the striking room 11 adjacent to the positioning pins 13 is unavoidably thin, apt to be broken under great torsion. And, likewise, the part (B) of the sidewall 121 of the striking blocks 12 adjacent to the positioning pins 13 has also a thin thickness, apt to be broken under great torsion.

In addition, as shown in FIGS. 3 and 4, a second conventional power tool possesses a striking set 20 in its front portion. The striking set 20 is composed of a striking room 21 having an empty zone 201, two striking blocks 22 installed in two sides of the striking room 21, two positioning pins 23 inserted through pin holes 211 of the striking room 21 and through holes 222 of the striking blocks 22, and a transmission shaft 24 provided with two restricting blocks 241 to be locked with the striking blocks 22 respectively. Like the first conventional one, when the striking set 20 is operated, one of the striking blocks 22 is to be hit to squeeze the restricting block 241 so that the transmission shaft 24 is activated to rotate clockwise or counterclockwise. However, being bored with the through hole 222 for being inserted with the positioning pin 23, the part (D), the thickness of a sidewall 221 of each of the striking blocks 22 abutting against the through hole 222, is relatively thin, enabling the positioning pin 23 to be broken in case of suffering excessive torsion. And, the part (E), the wall thickness of the striking room 21 adjacent to the pinhole 211, is also relatively thin to be easily broken under a larger torsion. Moreover, although the restricting blocks 241 are formed integral to possess a larger strength, the striking blocks 22 are to rotate only 180° to hit them again, relatively providing a small torsion to activate the transmission shaft to work with less efficiency.

SUMMARY OF THE INVENTION

The objective of this invention is to offer a striking device of a power tool.

The main characteristics of the invention are a striking room, two striking blocks and a transmission shaft. The striking room is provided with a pivotal restricting groove formed vertically at two sides of its inner wall respectively. A supporting surface is formed adjacent to two sides of each of the pivotal restricting grooves respectively, shaped as an arc. The striking blocks respectively have a projected pivot formed axially in their central portion. The projected pivot has its top and bottom pivotally connected to the striking room by pins pivotally inserted in pin holes of the upper and the lower wall of the striking room. Two sides of the projected pivot are extended with striking portions shaped as an arc. The transmission shaft is provided with two restricting blocks that have respectively a struck segment and a displacing segment located alternately. So, when one of the striking portions strikes bias at one of the struck segments, the other of the striking portions just leans on the supporting surface to activate the transmission shaft to rotate. Then the striking portion can pass through the corresponding displacing segment to carry out next strike when it moves away after striking. As the striking blocks are integrally formed with the projected pivots, they possess a strong strength to keep them from deformed while correspondingly striking the struck segments of the transmission shaft. When the striking blocks hit the transmission shaft with one of the striking portions, the other of the striking portions just contacts completely with the supporting surface, enabling the striking room to have a larger area to endure impact from the striking blocks, so as to prevent the striking room from damaged. In addition, the restricting blocks are formed integrally in the transmission shaft, respectively provided with the struck segment and the displacing segment located alternately, enabling the striking blocks to rotate for 360° before hitting the restricting blocks again, so that a rather strong torsion can be provided to activate the transmission shaft to work.

BRIEF DESCRIPTION OF DRAWINGS

This invention is better understood by referring to the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view of a first conventional striking device of a power tool;

FIG. 2 is a cross-sectional view of the first conventional striking device of a power tool;

FIG. 3 is an exploded perspective view of a second conventional striking device of a power tool;

FIG. 4 is a cross-sectional view of the second conventional striking device of a power tool;

FIG. 5 is a perspective view of a preferred embodiment of a striking device of a power tool in the present invention;

FIG. 6 is an exploded perspective view of the preferred embodiment of a striking device of a power tool in the present invention;

FIG. 7 is a cross-sectional view of the preferred embodiment of a striking device of a power tool in the present invention;

FIG. 8 is a perspective view of the preferred embodiment of a striking device of a power tool in the present invention, showing it being working;

FIG. 9 is a cross-sectional view of the preferred embodiment of a striking device of a power tool in the present invention, showing a striking block is striking on a transmission shaft; and

FIG. 10 is a cross-sectional view of the preferred embodiment of a striking device of a power tool in the present invention, showing the striking block is moving away the struck segment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 5˜7 show a preferred embodiment of a striking device of a power tool in the present invention. A striking set 3 is set in the front portion of the power tool, composed of a striking room 30, two striking blocks 40 and 50, and a transmission shaft 60 driven by a source (not shown).

The striking room 30 is provided with an accommodating space 31, an opening 32 bored at the center of its upper and lower wall 311 respectively, and a pivotal restricting groove 33 dug vertically in an inner surface of the wall 311 at its two sides respectively. Two sides of each of the pivotal restricting grooves 33 are respectively formed as a supporting surface 331 shaped as an arc. Bored on the upper and the lower wall 311 and based on the axial center of each of the pivotal restricting groove 33 are two corresponding pinholes 34. In addition, a shift block 35 is pivotally fitted in the opening 32 of the lower wall 311, engaged with a driving gear of a power (not shown in Figures) and provided with two engaging members 351 correspondingly located on its upper edge.

The striking blocks 40 and 50 respectively include a projected pivot 41 and 51 formed integrally along the axial central portion. The projected pivots 41 and 51 are respectively provided with an engaging tail 411 and 511 formed at the bottom for engaging with the engaging member 351, and two positioning holes 412 and 512 bored respectively at the top and the bottom of the projected pivot 41 and 51 to correspond to the pin holes 34. The positioning holes 412 and 512 are bored partly in the projected pivots 41 and 51, but just deep enough to let pins 42 and 52 be inserted via the pin holes 34 through therein, keeping the striking blocks 40 and 50 combined together between the upper and the lower pin holes 34. The outer surface of the projected pivots 41 and 51 is shaped as a pivotal restricting surface 413 and 513 to engage pivotally with the pivotal restricting grooves 33, so as to swing bias by pivoting on the pins 42 and 52. The inner side of the projected pivots 41 and 51 is formed as inner walls 414 and 514 respectively with a rather broad thickness. Extended outward from two sides of each of the projected pivots 41 and 51 are striking portions 43 and 53 integrally shaped as an arc, for correspondingly matching with the supporting surfaces 331. When the striking blocks 40 and 50 are installed in the striking room 30, the striking portions 43 and 53 are located in different levels without interfering with each other.

The transmission shaft 60 is provided with a pivotal engaging portion 61 formed in its intermediate portion with a larger diameter, for fitting in the opening 32 of upper wall 311 of the striking room 30, and a lower shaft 62 extended downward from the bottom of the pivotal engaging portion 61 to be located inside the striking room 30. There are two restricting blocks 63 and 64 formed integrally to be located axially and symmetrically around the lower shaft 62 through to its bottom. The restricting blocks 63 and 64 are respectively provided with a struck segment 631 and 641, and a displacing segment 632 and 642, positioned up and down alternately. The struck segments 631 and 641 are shaped protrudent and the displacing segments 632 and 642 are shaped concave. In addition, the restricting blocks 63 and 64 are also respectively provided with a guiding corner 633 and 643 formed at an edge of the displacing segment 632 and 642 for the striking block 40 and 50 to hit the struck segment 631 and 641 and then pass through the displacing segment 632 and 642 to carry out next striking. By means of the guiding corners 633 and 643, the striking block 40 and 50 can easily move away the restricting blocks 63 and 64 after striking.

In using, as shown in FIGS. 8˜10, when the striking room 30 is activated by a power to whirl clockwise or counterclockwise, the striking blocks 40 and 50, pivoting on the projected pivots 41 and 51 fitted in the pivotal restricting grooves 33, are to correspondingly rotate with a preset angle, so that one of the striking portions 43 and 53 is to hit one of the struck segments 631 and 641 to drive the transmission shaft 60 to spin clockwise or counterclockwise. By the time, a counterforce (P) fed back to the striking portions 43 and 53 from one of the struck segments 631 and 641 is able to be weakened as the other striking portions 43 and 53 just rest on the supporting surfaces 331 to scatter the counterforce (P) into smaller ones (P′) against the supporting surface 331 so that the striking room 30 may have a rather large surface to endure the impact from the striking blocks 40 and 50, preventing the striking room 30 from damaged. Of course, the pins 42 and 52 can also be protected from being damaged because the counterforce (P) is almost absorbed by the supporting surfaces 331. Next, the striking blocks 40 and 50 are to rotate with a preset angle to enable the striking portions 43 and 53 to immediately move away from the struck segments 631 and 641 and pass through the displacing segments 632 and 642 to carry out next strike. And, by means of the shift block 35, the striking blocks 40 and 50 can turn around another 360° to hit the struck segments 631 and 641 again with a larger torsion to make the transmission shaft 60 spin effectively.

The invention has the following advantages as can be seen from the foresaid description.

1. The striking blocks 40 and 50 are integrally formed, having the positioning holes 412 and 512 bored only partly in the projected pivots 41 and 51 so that the projected pivots can have a better strength. When the striking blocks 40 and 50 hit the transmission shaft 60 with one of the striking portions 43 and 53, the other of the striking portions 43 and 53 contact completely with the supporting surfaces 331, able to help scatter the counterforce (P) generated while striking, preventing the striking room 30 from damaged. And, as the counterforce (P) is totally scattered by the supporting surfaces 331, the pins 42 and 52 are not impacted at all, but used as pivots only.

2. The restricting blocks 63 and 64 are formed integrally from the pivotal engaging portion 61 to the bottom of the transmission shaft 60, able to enhance their strength not to be easily damaged. And, the struck segments 631 and 641 and the displacing segments 632 and 642 are formed integrally, located alternately so as to enable the striking blocks 40 and 50 to spin for 360° to hit the struck segments 631 and 642 again with an enlarged torsion, boosting the efficiency of the transmission shaft 60.

While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention. 

1. A striking device of a power tool, said power tool provided with a striking set installed in its front portion, said striking set comprising: a striking room provided with an accommodating space, an opening bored at a center of its upper and lower wall respectively, and a pivotal restricting groove dug vertically in an inner surface of its two sidewall respectively, two supporting surfaces formed as an arc and next to two sides of each of said pivotal restricting grooves, two pin holes bored correspondingly in said upper and said lower wall and located at an axial center of each said pivotal restricting groove, a shift block pivotally fitted in said opening of said lower wall and provided with two engaging members located on a circumference of its upper edge; two striking blocks respectively provided with a projected pivot formed integrally along their axial central portion, said projected pivots respectively provided with an engaging tail formed at a bottom for engaging with said engaging member, each said projected pivot having its top and bottom pivotally matched with said pin holes of said striking room by being fitted with pins, said projected pivot having its outer surface formed as a pivotal restricting surface to engage pivotally with the pivotal restricting grooves so as to swing bias by pivoting on said pins, a striking portion shaped as an arc to match with that of said supporting surface and extended from two sides of said projected pivot respectively, said striking portions located alternately without interfering with each other; and a transmission shaft provided with a pivotal engaging portion formed in its intermediate portion with a larger diameter for fitting in said opening of said upper wall of said striking room, a lower shaft extended downward from a bottom of said pivotal engaging portion to be located inside said striking room, and two restricting blocks formed integrally to be located axially and symmetrically around said lower shaft through to its bottom, each said restricting block provided with a struck segment and a displacing segment that are positioned up and down alternately so that one of said striking portions of said striking blocks can rotate with a preset angle in said striking room to hit corresponding said struck segments and the other said striking portion just contacts with said supporting surface to activate said transmission shaft to whirl, said striking blocks then rotating with a preset angle to enable said striking portion of said striking blocks to move away from said struck segment and pass through said displacing segment to carry out next striking, said striking blocks activated by said displacing blocks to rotate with a preset angle so as to hit again said restricting block of said transmission shaft to keep said transmission shaft rotated.
 2. The striking device of a power tool as claimed in claim 1, wherein said struck segments are shaped protrudent and said displacing segments are shaped concave, so that said striking blocks can correspondingly strike said struck segments and then pass through said displacing segments to carry out next striking, each said displacing segment of said restricting blocks provided with a guiding corner that is used to keep said striking block move away from said restricting block easily, so that said striking block can be activated by said shift block to turn around with an angle of 360° to hit said restricting block of said transmission shaft again to drive said transmission shaft to rotate.
 3. The striking device of a power tool as claimed in claim 1, wherein said projected pivot of each said striking block possesses a broad inner thickness, said projected pivot has a positioning hole bored at its top and bottom to correspond to said pin holes of said striking room, said positioning holes are bored partly in said projected pivots and letting said pins insert from said pin holes through therein, so as to keep said striking blocks installed between said pin holes and inside said striking room. 